运用稠密气体理论建立气粒两相流流动模型

APPLYING THEORY OF DENSE GAS TO MODEL GAS PARTICLE FLOW

循环流化床内的复杂流动特征使其工业放大较困难，迄今对其流动特征尚缺乏充足的理论解释。本文从流体力学及稠密气体分子运动的相关理论出发，定义了“颗粒温度”；对双颗粒碰撞分布函数建立了Ｂｏｌｔｚｍ ａｎ Ｉｎｔｅｇｒａｌ－ｄｉｆｆｅｒｅｎｔｉａｌ方程，简单介绍了该方程的求解方法，从而进一步推导出颗粒相的连续方程、动量方程、拟热能（颗粒温度）方程，给出了颗粒相的压力、粘度和关于颗粒温度传递系数的表达式，建立了完整的颗粒相湍流动力学模型，并把模拟结果与实验结果相比较，进一步验证了模型的科学合理性。

Complex hydrodynamic behavior of circulating fluidized beds makes difficulties with the scale up. It is well know that the large scale lateral solids segregation causes a complex two phase flow pattern which significantly influences their performance. Though some work has been done, many flow characteristics have no be well exptained therorically. The kinetic theory for granular flow based on the Chapamn Enskoy theory of dense gases and the relvant hydrodynamic theory were used to model the influences of direct particle particle collisions in the paper. Associated with the random motion of particles, a pseudo temperature was defined. Using a method of modeling transport mechanisms resulted in the well known Boltzman Integral differential Equation on a pair velocity distribution function. By solving the equation, we not only acquired the continuity equation, momentum equation and pseudo temperature equation, but also produced the formulations of particle pressure, viscosity and transport coefficient of particle temperature et al. Gas particle two phase kinetic model was also advanced completely. At the end, radial distribution of particles velocities and volume fractions cuas also afforded, which is used in the comparison between simulation and experimental results. By the comparison, it was clearly that the proposed model is successful in use.